Recently I wrote a class for program flow-graphs. Writing unit tests, it turned out, required more effort than the unit tests that I had written for other classes .
I was aware that when writing functions one must document the pre-conditions and the post-conditions. These I implemented as asserts. I usually felt that these were adequate. But when it came to the program flow-graph methods, the set of asserts was turning up to be just too messy
As I mentioned, the development of unit tests was turning out to be more difficult. The program flow-graph object to be used for the test had to be decided. What it would be transformed to was to be worked out. I found myself putting these down, in the test case file, as a file comment block. While doing that, I realized I was effectively specifying Pre-Conditions and Post-Conditions. I was saying, "Given this program graph object as the input, some set of attributes should change, and some set of attributes should remain invariant".
Light-Bulb event: Unit tests are statements of Pre-Conditions and Post-conditions.
What about asserts? I now regard these as micro unit tests that are embedded in the code.
PS: I hope to be more frequent in my posts in 2014:-)
Happy New Year.
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